1. Field of the Invention
The present disclosure relates to a channel estimation method of Impulse-Radio Ultra-Wideband (IR-UWB) wireless communications at the receiver.
2. Description of Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Ultra-wideband (UWB) radio is a rapidly evolving technology which is aimed primarily for indoor wireless communications and precision positioning applications. High achievable data rates and fine time resolution capabilities of UWB technology makes it attractive for wireless communications, networking, radar, imaging and positioning systems. In 2002, the U.S. Federal Communications Commission (FCC) allocated unlicensed spectrum for UWB communication, which resulted in an exponential growth of research in UWB technologies.
Several studies have addressed the channel estimation problem in UWB channels. Among these is maximum likelihood estimation of multi path components (MPCs) assuming very high rate sampling. Also, a pair of successive symbol-long segments is used for estimating the channel with one symbol acting as a dirty template for the other while the timing synchronization and estimation are performed by maximizing the correlation of the pair of successive symbol-long segments. The UWB channel has also been estimated using its Fourier coefficients. Compressive sensing is also applied for the UWB channel estimation problem by exploiting the channel sparsity. Among conventional estimation methods, none use a priori statistical information about the UWB channel and the rich structure of the sensing matrix.
UWB communications systems offer several advantages, including high data rates, high multipath resolution, low power requirements and simple transmitters. There are several challenges that accompany the advantages of UWB communication, however. The Nyquist sampling frequency for UWB signals is prohibitively high and is very difficult to realize using available analog-to-digital conversion technologies. Moreover, due to the huge bandwidth, a large number of multipath components (MPCs) are resolvable at the receiver and the transmitted energy is distributed over these MPCs. Since the transmitted energy levels in UWB systems are low (to minimize interference to other co-existing communications), the UWB receiver must estimate several MPCs to capture sufficient energy for successful communications. The channel estimation problem in UWB is therefore an important yet challenging task.